M Junaid Lakhani, Wahab Kadri, Hassan Mehdi, Houshang Sukhia, Asma Bano, Sania Yaqoob


Background: Impaction of the 3rd molar is a high incident problem occurring in up to 73% of
young adults in Europe. Appropriate follow-up routines and optimal timing for surgical
removal of the 3rd molars can be established in patients judged to be at increased risk of
impaction. The purpose of this study was to identify risk factors for mandibular 3rd molar
impaction in adolescent orthodontic patients and to establish anterior arch crowding as a
predictive model for mandibular 3rd molar impaction. Methods: Pre-treatment
Orthopantomogram (OPG) of 158 orthodontic patients with the evidence of anterior arch
crowding on pre-treatment study models were evaluated for mandibular third molar position.
Results: Out of 158 patients, 45 were male and 113 were female. Ninety-seven (61%) of the
patients showed anterior arch crowding with a space discrepancy of 5–10 mm calculated on
the pretreatment study models. Fifty-seven patients showed 107 third molar impactions.
Anterior arch crowding in these patients was ranging from 7–10 mm. Out of 107 impacted
third molars 73 were Mesioangular 14 were Distoangular 6 were Vertical and 14 were
Horizontal. Conclusion: If the arch size is smaller as compared to the tooth size the evidence
of lack of space would be there in anterior segment as crowding and in posterior segment as
3rd molar impaction.
Keywords: Mandibular third molar impaction; anterior arch crowding

Full Text:



Elsey MJ, Rock WP. Influence of orthodontic treatment on

development of third molars. Br J Oral Maxillofac Surg


Dachi SF, Howell FV. A survey of 3,874 routine full-mouth

radiographs. II. A study of impacted teeth. Oral Surg Oral Med Oral

Pathol 1961;14:1165–9.

Bishara SE, Andreasen G. Third molars: a review. Am J Orthod


Grover PS, Lorton L. The incidence of unerupted permanent teeth

and related clinical cases. Oral Surg Oral Med Oral Pathol


Björk A, Jensen E, Palling M. Mandibular growth and third molar

impaction. Acta Odont Scand 1956;14:231–71.

Björk A. Variations in the growth pattern of the human mandible:

longitudinal radiographic study by the implant method. J Dent Res

;42(Suppl 1)400–11.

Björk A. Prediction of mandibular growth rotation. Am J Orthod


Skieller V, Björk A, Linde-Hansen T. Prediction of mandibular

growth rotation evaluated from a longitudinal implant sample. Am J

Orthod 1984;86:359–70.

Richardson ME. The early developmental position of the lower third

molar relative to certain jaw dimensions. Angle Orthod


Richardson ME. Changes in lower third molar position in the young

adult, Am J Orthod Dentofacial Orthop 1992;102:320–7.

Richardson ER, Malhotra SK, Semenya K. Longitudinal study of

three views of mandibular third molar eruption in males. Am J

Orthod 1984;86:119–29.

Richardson ME. Development of the lower third molar from 10 to

years. Angle Orthod 1973;43:191–3.

Peterson LJ. Principles of management of impacted teeth. In:

Peterson LJ, Ellis E, Hupp JR, Tucker MR. (Editors). Contemporary

oral and maxillofacial surgery. Mosby-Year Book, St Louis


Richardson ME. The etiology and prediction of mandibular third

molar impaction. Angle Orthod 1977;47:165–72.

Capelli J Jr. Mandibular growth and third molar impaction in

extraction cases. Angle Orthod 1991;61:223–9.

Alling CC III, Alling RD. Indications for management of impacted

teeth. In: Alling CC III, Helfrick JF, Alling RD., (Editors). Impacted

teeth. WB Saunders, Philadelphia (1993).p.46–9.

Begg PR. Stone age man’s dentition: With reference to anatomically

correct occlusion, the etiology of malocclusion, and a technique for

its treatment. Am J Orthod 1954;40:298–312, 373–83, 517–31.

Murphy TR. Reduction of the dental arch by approximal attrition. Br

Dent J 1964;116:483–8.

Cavanaugh JJ. Third molar changes following second molar

extractions. Angle Orthod 1985;55:70–6.

Gooris CGM, Årtun J, Joondeph DR. Eruption of mandibular third

molars after second-molar extractions: a radiographic study. Am J

Orthod Dentofacial Orthop 1990;98:161–7.

Kim TW, Årtun J, Behbehani F, Artese F. Prevalence of third molar

impaction in orthodontic patients treated non extraction and with

extraction of four premolars. Am J Orthod Dentofacial Orthop


Baykul T, Saglam AA, Aydin U, Başak K. Incidence of cystic

changes in radiographically normal impacted lower third molar

follicles. Oral Surg Oral Med Oral Pathol Oral Radiol Endod


Al-Balkhi KM. The effect of different lower third molar conditions

on the recrowding of the lower anterior teeth in the absence of tight

interproximal contacts one year post orthodontic treatment: a pilot

study. J Contemp Dent Pract 2004;5(3):66–73.

Bishara SE, Jakobsen JR, Treder JE, Stasi MJ. Changes in the

maxillary and mandibular tooth size arch length relationship from

early adolescence to early adulthood. Am J Orthod Dentofac Orthop


Bishara SE, Treder TE, Damon P, Olsen M. Changes in the dental

arches and dentition between 25 and 45 years of age. Angle Orthod


Lundström A. Changes in crowding and spacing of the teeth with

age. Dent Pract 1968;19:218–24.

Sinclair PM, Little RM. Maturation of untreated normal occlusions.

Am J Orthod 983;83:114–23.


  • There are currently no refbacks.

Contact Number: +92-992-382571

email: [jamc] [@] []